ISP Config migration tool - peicemeal migration?

Hi all - can someone confirm what I have deduced from other posts:
1. After a (not dry) run of the migration tool, the source sites will continue to work.
2. Even after then running the bash script on the target, the source sites will still work.
and so therefore...
3. Only after switching DNS will the source sites stop being served from source and will then be served from target.
4. Even after all of this, the original web sites' files will remain of the source server.
Many thanks in advance

1) Yes. The source server is not touched or altered. The tool just extracts the configuration and imports it to the new server, during that step, it creates the data copy script which then copies the actual data and database contents over to the server. So the tool just reads from source server, it does not alter it.
2) Yes.
3) Yes. And you can switch back at any time by reversing the dns change again.
4) Yes.